The purpose of this study is to test the safety of a drug called BYL719 at different dose levels. The investigators want to find out what effects, good and/or bad, BYL719 has on the patient and breast cancer. BYL719 will be given with either letrozole or exemestane to patients with HR+ locally-advanced or metastatic breast cancer. When the recommended phase II dose of BYL719 in combination with letrozole or exemestane has been determined in the dose-finding phase, an additional 10 patients will be enrolled onto each arm in an expansion phase of the study. The purpose of the expansion phase is to further define the safety and feasibility of BYL719 in combination with letrozole or exemestane at the recommended phase II dose, and to estimate efficacy.

phase II dose of BYL719 (Arm A and Arm B) [ Time Frame: 2 years ] [ Designated as safety issue: No ]

Three patients will be enrolled onto Cohort 0 at the starting BYL719 dose of 300mg daily. All patients within a cohort will be observed for toxicity for one cycle (28 days) prior to entering additional patients.

For Arms C and D, the starting dose of BYL719 for the first cohort (Cohort 0) will be 250mg daily.when administered in combination with letrozole in a 1 week on, 1 week off schedule, or with exemestane in a 5 of 7 days weekly schedule, to patients with HR+ locally-advanced or metastatic breast cancer

Toxicity will be tabulated using the NCI Common Toxicity Criteria (CTCAE), version 4.0. A dose-limiting toxicity (DLT) is defined as an adverse event or abnormal laboratory value assessed as at least possibly related to the study medication, meeting any of the criteria listed in the table below, and occurring during Cycle 1 (≤ 28 days following the first dose of BYL719, including those in which the event started in Cycle 1 and the confirmation of the DLT occurs in a subsequent cycle).

efficacy of BYL719 (Arm A and Arm B) [ Time Frame: 2 years ] [ Designated as safety issue: No ]

For both the dose-finding phase and the expansion phase, patients may have stable or progressive disease on letrozole, and BYL719 will be added. A treatment cycle will consist of 28 days. Treatment doses for each AI will be fixed at the established dose. Patients will continue on treatment until progression of disease or unacceptable toxicity. The initial scan interval to assess disease status will be every two cycles (8 weeks) for the first four cycles (16 weeks), and then every 3rd cycle (12 weeks) thereafter.

Drug: BYL719
Drug: Letrozole

Experimental: Arm B: BYL719 plus Exemestane

For both the dose-finding phase and the expansion phase, patients may have stable or progressive disease on Exemestane, and BYL719 will be added. A treatment cycle will consist of 28 days. Treatment doses for each AI will be fixed at the established dose. Patients will continue on treatment until progression of disease or unacceptable toxicity. The initial scan interval to assess disease status will be every two cycles (8 weeks) for the first four cycles (16 weeks), and then every 3rd cycle (12 weeks) thereafter.

Drug: BYL719
Drug: Exemestane

Experimental: Arm C: BYL719 plus Letrozole

For both the dose-finding and expansion phases of Arms C and D, patients may have stable or progressive disease on letrozole or exemestane, and BYL719 will be added.Letrozole 2.5mg orally once daily with BYL719 given on days 1-7 and 15-21 of a 28 day cycle. The starting dose of BYL719 in Arms C will be 250mg daily.

Drug: BYL719
Drug: Letrozole

Experimental: Arm D: BYL719 plus Exemestane

For both the dose-finding and expansion phases of Arms C and D, patients may have stable or progressive disease on letrozole or exemestane, and BYL719 will be added. Exemestane 25mg orally once daily BYL719 Days 1-5, 8-12, 15-19, 22-26 of 28 day cycle. For Arm D, the established dose is 350mg for BYL719 we are currently enrolling 10 patients to the corresponding arm in the expansion phase of the study.

Drug: BYL719
Drug: Exemestane

Eligibility

Ages Eligible for Study:

18 Years and older (Adult, Senior)

Genders Eligible for Study:

Female

Accepts Healthy Volunteers:

No

Criteria

Inclusion Criteria:

Women age ≥ 18 years

Willing and able to comply with scheduled visits, treatment plan and laboratory tests

Willing and able to consent for biopsy of locally-advanced or metastatic breast cancer prior to treatment

Metastatic or locally-advanced unresectable breast cancer (includes metastatic or locally-advanced unresectable breast cancer which is diagnosed while on adjuvant letrozole or exemestane)

Histologically documented HR+ breast cancer in either the primary or metastatic setting, as defined by ER or PR ≥ 1%; results from the local lab are acceptable. Eligibility will not be affected by HER2 status.

The most recent treatment prior to enrollment must be one of the following (duration of treatment ≥2 weeks), and must have been adequately tolerated according the treating physician's judgment:

Letrozole or exemestane in combination with an experimental agent(s) on a clinical trial, provided that the experimental agent(s) is not a PI3K inhibitor or AKT inhibitor (experimental agent(s) must be discontinued for ≥ 3 weeks prior to starting study treatment)

Any number of prior endocrine therapies (including tamoxifen, fulvestrant and/or aromatase inhibitors in either the adjuvant or metastatic setting) and any number of prior chemotherapy regimens. Anti-cancer systemic therapy, such as chemotherapy or biologics or endocrine therapy, other than the AI, must be discontinued for ≥ 3 weeks prior to starting study treatment.

For the dose-finding phase, patients must also have stable disease OR progression of disease on the most recent treatment. For the expansion phase, patients must have progression of disease on the most recent treatment. Progression of disease is defined as new or worsening disease on objective imaging. Progression of disease includes recurrence diagnosed while on adjuvant letrozole or exemestane.

Postmenopausal women, as defined by one of the following (estradiol assay cutoff takes into account that the patient is on aromatase inhibitor therapy):

Age ≥ 55 years and one year or more of amenorrhea

Age < 55 years and one year or more of amenorrhea, with an estradiol assay within the post-menopausal range

Age < 55 years with prior hysterectomy but intact ovaries, with an estradiol assay within the post-menopausal range

Surgical menopause with bilateral oophorectomy

Ovarian suppression with a LH-RH agonist, with an estradiol assay within the post-menopausal range at baseline and periodically on-study Measurable or non-measurable disease per RECIST criteria v1.1

Fasting plasma glucose <140 mg/dl (may be on antiglycemic agents other than insulin). Fasting glucose measurement must be obtained at least 8 hours after the most recent caloric intake.

Ability to swallow oral medication

Willing to discontinue all herbal preparations / medications at least 7 days prior to the first dose of study drug and throughout the study. These include, but not limited to,St. John's wort, Kava, ephedra (ma huang), gingko biloba, dehydroepiandrosterone (DHEA), yohimbe, saw palmetto, and ginseng.

Exclusion Criteria:

Pregnant patients or women who are breast-feeding (patients must be postmenopausal, see Section 6.1.9)

Patients with central nervous system (CNS) involvement may participate if:

Clinically stable with respect to the CNS tumor at the time of screening and >4 weeks from prior therapy completion (including radiation and/or surgery) to the start of study treatment

Not receiving steroid therapy

Not receiving enzyme inducing anti-epileptic medications that were started for brain metastases (these include carbamazepine, phenytoin, phenobarbital, primidone, oxcarbazepine, topiramate, and vigabatrin) Prior PI3K inhibitor or AKT inhibitor (patients previously treated with everolimus are eligible, see rationale in Section 3.6)

History of toxicity to the most recent AI (letrozole or exemestane) that warrants cessation of the AI

Patients who have received radiotherapy ≤ 2 weeks prior to starting study treatment

Patients who have undergone major surgery ≤ 4 weeks prior to starting study treatment, who have not recovered from side effects of such procedure

Uncontrolled diabetes (as defined by fasting glucose ≥ 140mg/dL) and/or insulin-dependent diabetes. Fasting glucose measurement must be obtained at least 8 hours after the most recent caloric intake. Patients currently requiring the use of antiglycemic agents (other than insulin) may be enrolled if fasting glucose <140mg/dL.

Current need for chronic corticosteroid therapy (≥10mg of prednisone daily or an equivalent dose of other corticosteroid), or patients who have received systemic corticosteroids ≤ 2 weeks prior to starting study drug

Corrected QT interval (QTc) > 480 msec on screening ECG Patients who are currently receiving medication with a known risk of prolonging the QT interval or inducing Torsades de Pointes (TdP) and the treatment cannot either be discontinued or switched to a different medication prior to starting study drug treatment (see Section 9.6.3 and Appendix F)

Patients may not have a "currently active" second malignancy other than non-melanoma skin cancers. Patients are not considered to have a "currently active" malignancy if they have completed therapy and are considered by their physician to be at less than 30% risk of relapse.

Contacts and Locations

Choosing to participate in a study is an important personal decision. Talk with your doctor and family members or friends about deciding to join a study.
To learn more about this study, you or your doctor may contact the study research staff using the Contacts provided below.
For general information, see Learn About Clinical Studies.

Please refer to this study by its ClinicalTrials.gov identifier: NCT01870505